A tedder is an agricultural implement that has two or more, perhaps up to eight or ten, rotary members that have tines moving close to the surface of the ground as the tines are rotated in operation. The tines engage severed crop material lying on the ground and fluff the crop so that air can circulate through the crop more easily to cause the crop to dry. Tedders are typically used to fluff hay that had been cut previously and is lying flat on the ground. Once the cut hay crop is fluffed by the tedder, air can circulate better and allow the hay crop to be baled earlier. Rotary rakes are essentially the same type of equipment as tedders except that rotary rakes control the orientation of the tines in conjunction with the engagement of the crop to place the crop into a windrow for baling.
Tedders and rotary rakes are implements that can be mounted on the three-point hitch of a tractor to be operated through the field, or connected to the tractor hitch as a tow-behind implement, typically referred to as a pull-type implement, for movement across the field. In North America, the market for tedders and rotary rakes are primarily pull-type implements that are operably connected to the power take-off of the tractor to receive rotational power therefrom. The rotational power is delivered to a gearbox that distributes the rotational movement to the individual rake baskets for the rotation of the tines for engagement of the crop on the surface of the field.
Tedders and rotary rakes have a transversely extending operable configuration in which the individual rake baskets are placed in a generally linear manner transverse to opposing sides of the direction of travel of the implement and the prime mover to which the implement is connected. In this operable configuration, the rotating tines on the respective rake baskets engage the crop across the entire transverse width of the operating implement to manipulate the crop in the desired manner. To transport the tedder or rotary rake from one location to another, the implement can be placed into a transport configuration in which the individual rake baskets are displaced into a position that above and centrally positioned over a central transport frame.
For example, the rotary rake implement in U.S. Pat. No. 4,366,666, granted to Cornelis van der Lely on Jan. 4, 1983, a four rotor rotary rake has two rake baskets on opposing side of an implement centerline for operational configuration; however, the two outer rake baskets are pivotable into a vertical orientation to move into a transport configuration that has a narrower transport width than when the implement is in the operative configuration. As a contrast, the rotary rake, disclosed in U.S. Pat. No. 4,166,352, granted to Gregor Knusting on Sep. 4, 1979, has four rotors also, but are pivoted in a horizontal manner to trail behind one another. Other tedders and rotary rakes are manufactured with six or more individual rotors that convert into a transport position by vertically pivoting the outer rotors relative to the adjacent rotors and then vertically pivoting those adjacent rotors relative to the inner rotors, which provides a transport configuration that has two vertically oriented folded rotors and two horizontally oriented folded rotors, placing a substantial amount of weight on the inboard transport wheels.
Suspension of pull-type rotary rakes and tedders is not provided because a suspended frame can result in the individual rotor units bouncing relative to the ground while the implement is being operated. If these individual rotor units are bouncing, the tines will not track along the surface of the ground properly to engage the cut crop in order to manipulate the crop into either windrows or into a fluffed condition for subsequent raking into windrows. Therefore, although tedders and rotary rakes have been commercially available for decades, these implements remain unsuspended between the frame and the wheels supporting the frame for movement over the ground. The only suspension concept that has been incorporated into tedders and rotary rakes is to utilize a large balloon tire that flexes somewhat when an impact is encountered.
In U.S. Pat. No. 4,043,571, granted to Francois Guerbet on Aug. 23, 1977, an axle suspension system is disclosed in which the vehicle chassis has a hollow cross frame member that contains a rectangular bar that is surrounded by four rubber blocks with the bar oriented at about 45 degrees to the cross frame member so that one of rubber blocks can be located at the corner of the cross frame member to engage a flat surface of the bar, thus maintaining the bar within the cross frame member. The movement of the bar, which is connected to the wheel of the vehicle, compresses the rubber blocks to provide suspension between the wheel and the frame of the vehicle.
It would be desirable to provide suspension for a pull-type rotary rake and/or tedder, particularly for the transportation of the implement over the highway while in a folded transport configuration, without negatively impacting the operational efficiencies of the rake baskets in engaging the rotating tines with the cut crop lying on the field.